1. Field of the Invention
The present invention relates to a stack of folded sheets of, for example, wet tissues, wet nonwoven fabrics, dry tissues or dry nonwoven fabrics which are vertically arranged so as to facilitate a dispensing of the sheets one at a time.
2. Description of the Related Art
To keep their wet condition, wet sheets for wiping hands or babies"" crotches or for cleaning toilets or kitchens are airtightly sealed, for example, in hard containers or in bags made of a wrapping sheet. The containers or bags for such wet sheets are provided with an opening through which the wet sheets packaged therein can be withdrawn one at a time. In such containers or bags, the wet sheets are stacked vertically one on top of the other in an interfolded manner, and therefore, when the upper-most sheet is withdrawn through the opening of a container or bag, the underlying sheet is lifted and drawn to present an upper portion thereof in a readily accessible location above the opening.
FIG. 4 is an illustration of one example of the prior arts of this type, so-called pop-up stack of folded sheets.
As shown in FIG. 4, a plurality of folded sheets 1 are arranged in a stacked configuration. In this, each sheet is arranged in a Z-folded configuration to define a top flap portion 4, a central portion 2 and a bottom flap portion 6. The top flap portion 4 is folded about a fold line 3 upon the central portion 2, and the bottom flap portion 6 is folded about a fold line 5 under the central portion 2.
The thus-folded sheets 1 are stacked vertically one on top of each other in such a manner that the top flap portion 4 of the underlying sheet 1 lies between the central portion 2 and the bottom flap portion 6 of the overlying sheet 1, and that the top-flap portion 4 of the underlying sheet 1 and the bottom flap-portion 6 of the overlying sheet 1 overlap with each other in a predetermined width Lw (this is referred to as an overlapping portion). When the folded sheets are moistened like wet tissues, the adjacent sheets, i.e., the top flap portion 4 of the underlying sheet 1 and the bottom-flap portion 6 of the overlying sheet 1 are kept in airtight contact with each other at an overlapping portion thereof via a water film existing therebetween.
A stack of folded sheets 1 shown in FIG. 4 is packaged in a package 10, for example, a hard container of plastic or a bag of a soft wrapping sheet. The top face of the package 10 is formed with an opening 11 having a predetermined width.
When the upper-most folded sheet 1 of the stack is withdrawn through the opening 11, the underlying sheet is lifted and drawn via the overlapping portion to present of an upper end portion thereof from the opening 11 after the upper-most sheet has been withdrawn, thereby allowing a dispensing of the underlying sheet.
In case of folding each sheet to form a stack of this type, it is necessary to appropriately define the width Lw of overlapping portion of the overlying and underlying sheets. If the width Lw of overlapping portion is too short, the underlying sheet cannot follow the overlying sheet when the overlying sheet is withdrawn, and if so, the underlying sheet will remain in the package 10. On the other hand, if the width Lw of overlapping portion is too long, the amount of the underlying sheet which is pulled through the opening 11 will be increased after the overlying sheet has been withdrawn. As a result, the sheet tends to be dry.
For example, when the sheets are hydrophilic fibers-containing paper sheets or nonwoven fabrics and are moistened with water or solution, the width Lw is preferably 30 mm or so, ranging within 30xc2x120 mm to facilitate a stable dispensing.
With the sheets for wiping hands or babies crotches, the unfolded length L0 of a long side is 190 mm or 200 mm, generally falling between 150 and 230 mm or so. As shown in FIG. 5, the sheets are serially arranged and folded alternately in V and reverse V-configurations via the width Lw of overlapping portion. In the illustrated embodiment of FIG. 5, it is assumed that the width of overlapping portion is 30 mm, and the unfolded length L0 of the long side of the sheet is 200 mm. In that case, the width Ld of each two-folded (V-shaped) sheet is 100 mm, and the width Le of the overlapped sheets is-derived from the equation, 2xc3x97Ldxe2x88x92Lw, that is, Le is 170 mm, result in being extremely large. Accordingly, the width of the package that contains the stack of folded sheets will be also increased.
In case where each sheet is arranged in a Z-folded configuration (folded in three) as shown in FIG. 4, the width of the stacked sheets can be reduced.
For example, if the unfolded length L0 of the long side of the sheet shown in FIG. 4 is 200 mm and the width Lw of overlapping portion is 30 mm, the width La of the central portion 2 will be 85 mm. Specifically, in that case where the width La is 85 mm, the sum of the width Lb of the top flap portion 4 and the width Lc of the bottom flap portion 6, i.e., the sum of Lb and Lc is 115 mm (200xe2x88x9285=115), and, in addition, the width Lw of overlapping portion can be set as 30 mm (115xe2x88x9285=30).
Accordingly, the width of the stack of folded sheets shown in FIG. 4 can be reduced to a half of the width thereof of FIG. 5. However, in order to further reduce the width of the package 10 so that such small packages are available for portable applications and can be stored even in narrow spaces, the stack of two-folded sheets as shown in FIG. 5 and the stack of three-folded sheets as shown in FIG. 4 have their limitations for such purposes. Namely, in order that the width Lw of overlapping portion is appropriately defined and the width of the stack is reduced in each stack of two-folded or three-folded sheets, the unfolded length L0 of the long side of the sheets must be short. In other words, it is necessary to downsize the individual sheets.
However, if the unfolded length L0 of the sheet becomes short, it is impossible to ensure a satisfactory sheet area enough for wiping operations to cause any inconvenience for users when the sheets are withdrawn from the package 10 and used for wiping hands or babies"" crotches.
An object of the present invention is to provide a stack of folded sheets in which the width of overlapping portion of the overlying and underlying sheets therein can be appropriately defined, and the width of the stack can be reduced, without downsizing the individual sheets.
According to an aspect of the invention, a stack of sheets comprising a plurality of individually folded sheets which are stacked vertically one on top of the other via an overlapping portion having a predetermined width so that an underlying sheet is lifted along with an overlying sheet when the overlying sheet is withdrawn,
wherein each sheet is folded about fold lines all parallel to one side of the sheet to define two central portions having the same width, a top flap portion folded upward upon one central portion, and a bottom flap portion folded downward under the other central portion, and
the folded sheets are stacked up so that the odd-numbered sheets and the even-numbered sheets are alternately arranged to orient a first fold line of each odd-numbered sheet in the opposite direction of a first fold line of each even-numbered sheet, and that the top flap portion of the underlying sheet overlies the bottom flap portion of the overlying sheet to define the overlapping portion.
For example, the sheets are moistened with water or solution, and the width Lw of overlapping portion is 30xc2x120 mm, more preferably 30xc2x110 mm.
In the stack of sheets in which the dimensions of each folded sheet are defined to satisfy L2+L3xe2x88x92Lw=L1, if the unfolded length L0 of each sheet is expressed by L0=2xc3x97L1+L2+L3, wherein L1 indicates the width of the central portions, L2 indicates the width of the top flap portion, and L3 indicates the width of the bottom flap portion.
Also preferably, the stack of folded sheets is packaged in a hard or soft package having an access opening in the top face thereof to facilitate a dispensing of the sheets one at a time through the access opening.
In the stack of sheets of the invention, each sheet is folded into four i.e., into a W-folded configuration, and the odd-numbered sheets and the even-numbered sheets are alternately arranged in opposite directions. In this, the width dimensions of each four-folded sheet are specifically defined, and as a result, the overall width of the stack can be shortened in comparison with the typical stacks of V-folded or Z-folded sheets, in addition, the width of overlapping portion of the overlying and underlying sheets can be 30xc2x120 mm.